What is Delta Joint Replacement?

Reverse shoulder replacement surgery brings immense hope to patients whose shoulder does not function properly, when all conventional treatment methods and surgery has failed. The most common reasons that may lead to this surgery include osteoarthritis, rotator cuff problems, pseudoparalytic shoulder and cuff tear arthropathy. The reverse shoulder replacement surgery guarantees pain relief and a stable functioning of the shoulder. Before going into the details of the surgery, it is important to have a basic understanding of the anatomy of our shoulder.

Our shoulder is made up of three bones, namely the scapula (shoulder blade), the humerus (upper arm bone), and the clavicle (collarbone). The humerus is connected to the scapula by the rotator cuff which is formed by the tendons of four muscles (supraspinatus, teres minor, infraspinatus, and subscapularis). The glenoid which is a very thin and flat portion of the scapula forms the socket of the shoulder. The humeral head of the shoulder or the top end of the humerus has the shape of a ball and is held against the socket with the help of muscles and ligaments. The traditional shoulder replacements were designed to replicate this shoulder structure by using a thin, shallow plastic cup for the socket and a metal ball for the ball of the humerus. But the lack of a properly functioning rotator cuff to hold the metal ball intact in the plastic socket caused quick wear and tear of the plastic socket by the metal. The reverse shoulder replacement surgery procedure was developed as a solution to this problem.

How is Reverse Rotator Cuff Surgery Performed?

In the reverse shoulder replacement surgery the position of the socket and the ball are reversed which means that the humeral head (ball) is placed where the socket used to be and the socket is placed where the humeral head used to be. This new design makes the shoulder joint stable and function without a rotator cuff. The reverse artificial shoulder joint consists of a humeral component (humeral head) and a glenoid component (socket). The humeral component is a combination of a metal stem that is attached to the marrow cavity of the upper humerus with a plastic socket on top of the metal stem. This plastic is very tough and withstands wear and tear. The glenoid component consists of a metal base plate that is fitted into a small peg hole that is drilled into the bone and held tightly with screws inserted through the metal plate into the bone. A metal ball is attached to this base plate that fits into the plastic socket of the humeral component.

Before surgery you will be given general anesthesia to put you to sleep. In this procedure, the surgeon makes an incision through the skin and then separates blood vessels and the nerves and moves them aside. He then cuts into the joint capsule to enter the shoulder joint. At this point, the surgeon smoothes the ends and the replacement parts are attached. The metal ball component is attached to the shoulder bone and the cup-shaped socket is attached to the top of the upper arm bone.

Reverse Shoulder Replacement Risks

Similar to all other surgeries, the reverse shoulder replacement surgery may also cause certain complications. A few of the most common problems that may occur following a reverse shoulder replacement surgery include infection, problems due to the anesthesia, loosening of the joints, dislocation of the artificial shoulder, fracture and injury to the nerve or blood vessel. Although this is a very effective procedure, it is not for everyone. Reverse shoulder replacement surgery is not recommended for people having infection, poor health conditions, osteoporosis and severe weakness of the muscles around the shoulder.